Don't just add water, add mercedes coolant 50/50 mix.
Or better yet, if you lost alot of water, find the problem, maybe the plastic neck that rubber hose attaches to, and fix it and refill fresh.

give more details. did you run the car long overheating or was it just a momentary rise in temp before you shut it off???


maybe no damage if short duration overheat.

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
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1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD